Question about red eared slider turtles. We love our turtles but they have just grown way to big what can wedo

I have 2 RES one male one female. We have had them for over a year when I bought them the store owner told me they wouldnt get any bigger. Well she was mistaken the female is now 10" from head to tail and 7" accross the male is 81/2" long and 6" accross. They now are very aggressive towards each other him more than her he will bite on to her and not let go so now her back end is all chewed up and raw. I have a 50 gallon tank its not big enough for either of them anymore and I dont know what to do with them. with our living situation right now it would probably be best to find them new homes but nobody wants them. I called the pet store owner and she told me she would tak ethem back but right now her tank is full and i would have to wait until the others sold before vringing mine down. We love them but we just dont have the time or finances for them anymore. Does anyone have any suggestions on what i can do with them. I know i have to seperate them but but how not enough room in thetank